I have a 99 blazer lt with 250,000 miles on it. It has the 4.3 vortec motor. I took it in for maintenance and was informed that my engine is showing sign of blow by. Something a about vacuum pressure. Now my mechanic didn't say I needed some horribly expensive repair but my motor is starting to show its age.

Can someone please explain to me how bad off I might be. I love my blazer and have every intention of giving it a new engine. I just need time to save for it. Any input would be welcome.

 

To me, 'blow by' means oil is getting past the piston rings into the combustion chamber, meaning it's time for a cylinder honing and new rings, or cylinder re-boring with new rings.

 

like riddle said. your truck is starting to burn oil. you are loosing vacuum pressure because the piston rings are wore out and letting oil by, if they are letting oil by, they are not "pulling" as much air in as they used to. another way to put it into numbers would be a compression check.